The Titans are making the move to a power running offense. To be a power running offense, you need a running back that is a "battering ram." Chris Johnson has never been and will never be that type of running back. That is why they went out and signed Shonn Greene. But what happens if Greene gets hurt and has to miss significant time?
That is exactly why Jackie Battle needs to be on this roster. He can get those tough yards that CJ cannot get in a pinch, and that is very important to the offensive set that they are trying to run.
Battle will need to play special teams, but I am sure he would be willing to do that in order to have a spot on an NFL roster. As I posted this morning, they can keep Battle on the roster without having to cut anyone that would really come back to haunt them.